This invention relates to an aqueous colorant composition packaged in a water-soluble film, preferably a film of polyvinyl alcohol. The colorants are chromogens having a poly(oxyalkylene) substituent, which renders the colorant liquid, water-soluble and inhibits water present in the colorant composition from degrading the packaging film.
Colorants useful in the present invention, poly(oxyalkylene) substituted chromogens, and their synthesis are well known. Use of such colorants as fugitive tints for temporarily color coating textile fibers is disclosed in the following United States patents:
______________________________________ U.S. PAT. INVENTOR TITLE NO. ______________________________________ Hauser et al. Tint Compositions For Nylon Having 4,144,028 Improved Fugitivity Properties Brendle Ester Capped Alkyleneoxy Fugitive 4,167,510 Tints and Method For Producing Same Keller et al. Thiophene Based Fugitive Colorants 4,601,725 ______________________________________
These colorants are liquid at ambient temperature and, depending on the nature of the poly(oxyalkylene) substituent, e.g., the relative ethylene oxide to propylene oxide content, and terminal group, they can be made to be soluble or dispersible in a range of aqueous and oleophilic solvents. Examples of the versatility of these colorants are disclosed in the following United States patents:
______________________________________ U.S. PAT. INVENTOR TITLE NO. ______________________________________ Hauser et al. Water-Soluble, Non-Polar Solvent- 4,113,721 Soluble Ethyleneoxy-Propyleneoxy containing Fugitive Tints Kuhn Liquid-Water-Insoluble Polymeric 4,141,684 Colorants and Aqueous Dispersions Containing Same Harris Tint Compositions Useful For 4,871,371 Providing Coloration To Aqueous and Non-Aqueous Liquids ______________________________________
The poly(oxyalkylene) substituted chromogens have also been used in washable ink compositions as disclosed in the following patents:
______________________________________ U.S. PAT. INVENTOR TITLE NO. ______________________________________ Kluger et al. Methine Colorants And Washable Ink 4,981,516 Compositions Containing Methine Colorants Kluger et al. Washable Ink Compositions 5,043,013 ______________________________________
All of the aforementioned United States patents are incorporated by reference.
Another application for these colorants has been as spray pattern indicators for the application of agricultural chemicals. For example, the colorant may be dissolved in an aqueous agricultural chemical solution and sprayed on turf grass; areas of application are identified by a visible tint. The colorant may be washed off the grass by rain or watering. Spray pattern indicators are sold by Milliken Chemical, a Division of Milliken & Company of Spartanburg, S.C. as colorant concentrates under the trademark BLAZON.RTM.. While these colorants have excellent fugitivity and are easy to clean up, it is, nevertheless desirable to avoid contact and handling of the colorant concentrate.
Poly(oxyalkylene) substituted chromogens may be conveniently manufactured in an aqueous solvent and the colorant composition can contain up to 30 wt. % water. It is desirable both from an energy savings and performance view point to retain a significant amount of water in the colorant composition; the water lowers the viscosity of the composition, which assists in the subsequent dispersion of the colorant.
Various approaches have been taken for employing water-soluble films to package aqueous compositions or other material which can have a deleterious effect on such films. For example, multiple layer films having a water-soluble outer layer and a water insoluble inner layer are disclosed in the following U.S. patents:
______________________________________ U.S. PAT. INVENTOR TITLE NO. ______________________________________ Scheier Container 3,790,067 Haq Packaging Film and Packaging Of 4,416,791 Detergent Compositions Therewith ______________________________________
The outer layer dissolves when the package is placed in water causing the inner layer to weaken and release its contents.
Aggressive chemical compositions, especially alkaline and borate-containing detergents, have been stored in water-soluble polyvinyl alcohol films which are modified to include a nonhydrolizable comonomer, examples of which are disclosed in the following patents:
______________________________________ U.S. PAT. INVENTOR TITLE NO. ______________________________________ Yang et al. PVA Films With Nonhydrolizable 4,747,976 Anionic Comonomers For Packaging Detergents Yang et al. Films From PVA Modified With 4,885,105 Nonhydrolizable Anionic Comonomers ______________________________________
Kennedy, U.S. Pat. No. 4,973,416, discloses an aqueous liquid laundry detergent packaged in a water-soluble film, preferably polyvinyl alcohol. The detergent comprises about 10 to 24 wt. % water and an organic neutralization system, such as an alkanolamine. The detergent also may contain a surfactant, a builder and a solvent system, for example, ethanol and propylene glycol. The water-soluble film maintains its integrity due to the critical level of water in the liquid laundry detergent and incorporation of the neutralization system.
Gelatin capsules filled with aqueous solutions containing "more than 10% water" are prepared in Kreuger, U.S. Pat. No. 2,580,683, by incorporating a hygroscopic material, such as dextrins, pectins or calcium or magnesium salts, into the solution. Griffin, U.S. Pat. No. 2,667,268, discloses gelatin capsules filled with an aqueous solution containing as much as 25% or more water by incorporating from 50 to 95% of an inhibitor, such as a poly(oxyalkylene) ether of an aliphatic polyol. Finally, water-soluble chemicals are provided in a gelatin capsule by Palermo et al., U.S. Pat. No. 2,780,355, by dissolving the water-soluble chemical in a liquid water-soluble hygroscopic organic liquid containing from 60 to 40 units of ethylene oxide per molecule, such as polyethylene glycols or fatty esters of polyethylene glycols.
The aforementioned approaches all have the disadvantage of requiring specialty films or additives to prevent the premature deterioration of the packaging.